import_viewer: fix counter upsert race + add explicit slot field

Pre-materialize ViewerEventCounters before the mission loop so in-flight
Adds are visible to subsequent iterations sharing the same (EventKey, Period);
add optional ImportMission.Slot field so callers can supply weekly slot identity
(2 or 3) rather than relying on the LotType-derived default of 1.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

SVSim.EmulatedEntrypoint/Controllers/AdminController.cs

@@ -279,6 +279,31 @@ public class AdminController : SVSimController
                 .ToDictionaryAsync(c => c.Id);
             var nowUtc = DateTimeOffset.UtcNow;
 
+            // Resolve counter keys for all missions up-front so we can load existing counters
+            // in one query and avoid duplicate-Add races when two missions share the same
+            // (EventKey, Period) within the same import batch.
+            var resolvedCounterKeys = new Dictionary<int, (string EventKey, string Period)>();
+            foreach (var m in missions)
+            {
+                if (!catalogs.TryGetValue(m.MissionId, out var cat)) continue;
+                var r = ResolveMissionCounter(cat, nowUtc);
+                if (r is not null)
+                    resolvedCounterKeys[m.MissionId] = r.Value;
+            }
+
+            // Collect all distinct (EventKey, Period) pairs we will touch.
+            var allEventKeys = resolvedCounterKeys.Values.Select(v => v.EventKey).Distinct().ToList();
+            var allPeriods   = resolvedCounterKeys.Values.Select(v => v.Period).Distinct().ToList();
+
+            // Load existing counters in one query (widens slightly; filter in memory below — fine for small N).
+            var existingCounters = await _dbContext.ViewerEventCounters
+                .Where(c => c.ViewerId == viewer.Id
+                         && allEventKeys.Contains(c.EventKey)
+                         && allPeriods.Contains(c.Period))
+                .ToListAsync();
+            var counterCache = existingCounters
+                .ToDictionary(c => (c.EventKey, c.Period));
+
             foreach (var m in missions)
             {
                 if (!catalogs.TryGetValue(m.MissionId, out var cat))
@@ -289,35 +314,30 @@ public class AdminController : SVSimController
                 viewer.Missions.Add(new ViewerMission
                 {
                     MissionCatalogId = cat.Id,
-                    Slot = cat.LotType == 6 ? 0 : 1,
+                    Slot = m.Slot ?? (cat.LotType == 6 ? 0 : 1),
                     MissionStatus = m.MissionStatus,
                     AssignedAt = DateTimeOffset.UtcNow.ToUnixTimeSeconds(),
                     ClaimedAt = null
                 });
 
-                var resolved = ResolveMissionCounter(cat, nowUtc);
+                if (!resolvedCounterKeys.TryGetValue(m.MissionId, out var resolved))
-                if (resolved is null)
                 {
                     skippedMissionCounterIds.Add(m.MissionId);
                     continue;
                 }
-                var (eventKey, period) = resolved.Value;
+                var (eventKey, period) = resolved;
-                var existingCounter = await _dbContext.ViewerEventCounters
+                if (!counterCache.TryGetValue((eventKey, period), out var counter))
-                    .FirstOrDefaultAsync(c => c.ViewerId == viewer.Id && c.EventKey == eventKey && c.Period == period);
-                if (existingCounter is null)
                 {
-                    _dbContext.ViewerEventCounters.Add(new ViewerEventCounter
+                    counter = new ViewerEventCounter
                     {
                         ViewerId = viewer.Id,
                         EventKey = eventKey,
                         Period = period,
-                        Count = m.TotalCount
+                    };
-                    });
+                    _dbContext.ViewerEventCounters.Add(counter);
-                }
+                    counterCache[(eventKey, period)] = counter;
-                else
-                {
-                    existingCounter.Count = m.TotalCount;
                 }
+                counter.Count = m.TotalCount;
             }
         }
 

SVSim.EmulatedEntrypoint/Models/Dtos/Requests/Admin/ImportViewerRequest.cs

@@ -93,6 +93,9 @@ public class ImportMission
 
     [JsonPropertyName("total_count")]
     public int TotalCount { get; set; }
+
+    [JsonPropertyName("slot")]
+    public int? Slot { get; set; }
 }
 
 public class ImportMissionMeta

SVSim.UnitTests/Controllers/AdminControllerTests.cs

@@ -585,4 +585,96 @@ public class AdminControllerTests
         Assert.That(verifyDb3.ViewerMissions.Count(m => m.MissionCatalogId == 9002), Is.EqualTo(1));
         Assert.That(verifyDb3.ViewerEventCounters.Any(), Is.False);
     }
+
+    [Test]
+    public async Task ImportViewer_Missions_TwoMissionsSharingEventType_SingleCounterUpsert()
+    {
+        // Two weekly missions (LotType=2) share the same EventType — same (EventKey, WeekKey)
+        // period — but occupy different slots (1 and 2 via explicit slot override) so the slot
+        // unique-index is satisfied. Without the pre-materialized counterCache the second DB read
+        // won't see the first mission's pending Add → duplicate insert / unique-constraint failure.
+        // With the fix both missions upsert the SAME counter, resulting in exactly one row.
+        using var factory = new SVSimTestFactory();
+        using (var seedScope = factory.Services.CreateScope())
+        {
+            var seedDb = seedScope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+            seedDb.MissionCatalog.AddRange(
+                new MissionCatalogEntry { Id = 9003, LotType = 2, EventType = "battle_win_total", EventArg = null },
+                new MissionCatalogEntry { Id = 9004, LotType = 2, EventType = "battle_win_total", EventArg = null });
+            await seedDb.SaveChangesAsync();
+        }
+        var client = factory.CreateClient();
+        ulong steamId = 70000000000000005UL;
+
+        var resp = await client.PostAsJsonAsync("/admin/import_viewer", new ImportViewerRequest
+        {
+            SteamId = steamId,
+            Missions = new List<ImportMission>
+            {
+                new() { MissionId = 9003, MissionStatus = 1, TotalCount = 10, Slot = 1 },
+                new() { MissionId = 9004, MissionStatus = 1, TotalCount = 10, Slot = 2 },
+            }
+        });
+        resp.EnsureSuccessStatusCode();
+        var body = await resp.Content.ReadFromJsonAsync<ImportViewerResponse>(JsonOptions);
+        Assert.That(body!.SkippedMissionCount, Is.EqualTo(0));
+        Assert.That(body.SkippedMissionCounterCount, Is.EqualTo(0));
+
+        using var verifyScope = factory.Services.CreateScope();
+        var verifyDb = verifyScope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+        var viewerId = await verifyDb.Viewers
+            .Where(v => v.SocialAccountConnections
+                .Any(s => s.AccountType == SocialAccountType.Steam && s.AccountId == steamId))
+            .Select(v => v.Id).SingleAsync();
+
+        // Must be exactly ONE counter row for (EventKey="battle_win_total"), not two.
+        Assert.That(
+            verifyDb.ViewerEventCounters.Count(c => c.ViewerId == viewerId && c.EventKey == "battle_win_total"),
+            Is.EqualTo(1));
+        Assert.That(
+            verifyDb.ViewerEventCounters
+                .Single(c => c.ViewerId == viewerId && c.EventKey == "battle_win_total").Count,
+            Is.EqualTo(10));
+    }
+
+    [Test]
+    public async Task ImportViewer_Missions_ExplicitSlotRoundTrips()
+    {
+        // A weekly catalog mission (LotType=2) posted with an explicit slot=3 must persist Slot=3,
+        // not fall back to the LotType-derived default of 1.
+        using var factory = new SVSimTestFactory();
+        using (var seedScope = factory.Services.CreateScope())
+        {
+            var seedDb = seedScope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+            seedDb.MissionCatalog.Add(new MissionCatalogEntry
+            {
+                Id = 9005, LotType = 2 /* weekly */,
+                EventType = null, EventArg = null
+            });
+            await seedDb.SaveChangesAsync();
+        }
+        var client = factory.CreateClient();
+        ulong steamId = 70000000000000006UL;
+
+        var resp = await client.PostAsJsonAsync("/admin/import_viewer", new ImportViewerRequest
+        {
+            SteamId = steamId,
+            Missions = new List<ImportMission>
+            {
+                new() { MissionId = 9005, MissionStatus = 1, TotalCount = 0, Slot = 3 }
+            }
+        });
+        resp.EnsureSuccessStatusCode();
+
+        using var verifyScope = factory.Services.CreateScope();
+        var verifyDb = verifyScope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+        var viewerId = await verifyDb.Viewers
+            .Where(v => v.SocialAccountConnections
+                .Any(s => s.AccountType == SocialAccountType.Steam && s.AccountId == steamId))
+            .Select(v => v.Id).SingleAsync();
+
+        var mission = await verifyDb.ViewerMissions
+            .SingleAsync(m => m.ViewerId == viewerId && m.MissionCatalogId == 9005);
+        Assert.That(mission.Slot, Is.EqualTo(3));
+    }
 }